Gamic reproduction capacity of native species colonizers of flysch landslides

Gamic reproduction capacity of native species colonizers of Flysch landslides

Piccinin Lisa and Scotton Michele
Department of Environmental Agronomy and Crop Production, University of Padova (Italy)
Agripolis, 35020 Legnaro (PD) – Italy. E_mail: lisa.piccinin@unipd.it

Introduction
The growing interest for land reclamation with low impact methods, where native species are used, increasethe need to study plant species, that are good colonizers in landslide areas. In this study we analysed some quantitative and qualitative features of the seed production of five species that are normally present in landslide, spontaneously re-colonized surfaces in order to value their suitability for nursery propagation and seed cultivation.

Materials and Methods
The plants of the studiedspecies were collected on the historical landslide of Valmorel in Belluno province (North-Eastern Italy). The elevation is between 800 and 1000 m a.s.l.. The geologic substrata are Flysch and Calcareous moraines. The climate in this area is characterized of an equinoctial rainfall distribution with annual rainfall of 1800 mm and mean annual temperature of 9,7°C. At the beginning (1934), thelandslide was 26 ha large. On the landslide, some land reclamation works were carried out about 1950, but the species that now cover the soil are spontaneous (Scotton and Piccinin, 2004). For the study, the following 5 species was chosen for their abundance or frequency on the landslide area: Brachypodium rupestre ssp. caespitosum (Bra rup), Calamagrostis varia (Cal var), Carex flacca (Car fla), Melicanutans (Mel nut) and Molinia arundinacea (Mol aru). The considered features were surveyed or analysed on tree plants for each species observed and collected during the summer 2000. They were: number of the seeds per inflorescence, number of flowering stems per tussock, number of tillers per tussock, inflorescence height above the soil, 1000 seeds weight, number of flowering stems per unit surface,germinability of seed with the following four pre-germination treatments: 1. prechill+KNO3 (0,2 % in H2O solution), 2. prechill+AG3 (0,05% in H2O solution), 3. prechill, 4. only H2O. Prechill conditions were 4°C for 40 days, germinating conditions were 20°C for 16 hours of light and 10°C for 8 hours of dark.

Results
The results about the biometric features are contained in Table 1. Withreference to the seeds number per plant, the highest values were obtained in Molinia arundinacea, Calamagrostis varia and Carex flacca, the lowest in Melica nutans, while Brachypodium rupestre ssp. caespitosum showed intermediate values. Calmagrostis varia had the highest number of stems with inflorescence per tussock. Multiplying this value by the number of tussock per unit surface, we obtained thatmolinia arundinacea and Calamagrostis varia showed

Table 1: Biometric features of the five studied species (s.d.=standard deviation) .
| |Species * |
| |Bra rup |Cal var |Car fla|Mel nut |Mol aru |

Feature |mean |s.d. |mean |s.d. |mean |s.d. |mean |s.d |mean |s.d. | |Number of non-flowering tillers tussock-1 |7.3 |3.5 |11.7 |4.7 |4.0 |1.0 |8.3 |1.5 |7.7 |1.5 | |Height of flowering stems (cm) |91 |11 |106 |12 |72 |11 |60 |3 |147 |16 | |Number of flowering stems tussock-1 |2.3 |0.6 |3.7 |3.1 |2.7 |1.5 |2.3 |0.6 |2.3 |1.5 | |Number of flowering stems m-2|9.3 |11.3 |25.0 |17.6 |7.5 |5.0 |7.4 |3.9 |61.3 |71.2 | |Number of seeds per flowering stem |74.0 |14.7 |230.3 |40.7 |178.3 |14.0 |10.7 |1.2 |269.7 |157.6 | |Number of germinated seeds inflorescence-1 |37.0 |7.4 |62.2 |11.0 |3.6 |0.3 |4.9 |0.5 |16.2 |9.5 | |1000 seeds weight (g) |1.9515 |- |0.1423 |- |0.8820 |- |2.4813 |- |0.5508 |- | |*. See materials and methods.
higher number of tillers with...